Passive Location In Weak Signal Detection And Extraction Technology

Localizing and tracking of commonly commercial planes, helicopters and cruise missiles are important subjects in radio domain. As a result of the development of "electronic war", radar's increasingly important status and functions, and the challenge of radar's four menaces (i. e. electronic reconnaissance and interfering, super lower aircrafts and cruise missiles, concealed aircrafts and high speed anti-radiation missiles), radar systems have taken a great change. Consequently, the passive radar which were a kind of special bistatic radars were emerged. The passive radar has the capability of anti-radiation and anti-electronic reconnaissance because it can detect moving targets by using the other radiant signal and not eradiate signal by itself. Combined with the Innovative Foundation Project in High Technological Development-Plan of Ministry of National Science and Technology (i.e. a research on passive localizing system based on a non-co-operative transmitter like as Television and FM broadcast), we investigated on signal detection and estimation methods in passive localizing system in detail. Our works included signal detection,high accuracy DOA (Direction of arrival) estimation, high accuracy TOA (Time delay of arrival) estimation, high accuracy frequency estimation, and Doppler frequency estimation. The main distributions of the author are as follows: 1. Establish a arithmetic model of the passive localizing system and analyse its key techqiques. 2. Study the techniques of signal detection for the passive localizing system and put forward a constraining interference algorithm based on space region filtering. 3. Investigate on the algorithms of frequency and Doppler frequency estimation for the passive localizing system. We bring forward a moving target detection method based on bi-sample rate. 4. Work over the algorithm of DOA for the passive localizing system. We suggest a digital multi-booms algorithm of DOA based on FFT.